Preheat oven at 160C.
Beat the egg yolks until almost white (or ribbon stage, Google if you are not sure what this is)
Add the rest of the egg yolk ingredients and beat it to a runny paste.
Make the meringue by beating the egg whites and cream of tar tar till ribbon stage.
Add the stevia or sugar into the meringue, and beat to stiff peaks.
Add 1/3 of the meringue at a time to the egg yolk mixture. Be careful not to deflate the meringue.
Bake for 60 minutes in a 21 cm tube pan with a pan of water just below the cake.
Once baked, remove from the oven and turn it upside down. When cooled, remove from the mold.